U.S. patent application number 14/297185 was filed with the patent office on 2017-07-13 for compositions for use in fused filament 3d fabrication and method for manufacturing same.
The applicant listed for this patent is Arevo, Inc.. Invention is credited to Hemant Bheda, Kunal Patel.
Application Number | 20170198104 14/297185 |
Document ID | / |
Family ID | 59275437 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170198104 |
Kind Code |
A1 |
Bheda; Hemant ; et
al. |
July 13, 2017 |
COMPOSITIONS FOR USE IN FUSED FILAMENT 3D FABRICATION AND METHOD
FOR MANUFACTURING SAME
Abstract
A method for forming a blended material for use as a deposition
material in a fused filament fabrication (FFF) printer is provided.
A semi-crystalline material and an amorphous material are
physically mixed at an appropriate ratio. The mixed material is
then heated to a temperature that is above the melting point of the
semi-crystalline material and above the glass transition
temperature of the amorphous material to form a blended material.
The blended material is then extruded through an extruder die for
use in the FFF printer.
Inventors: |
Bheda; Hemant; (Saratoga,
CA) ; Patel; Kunal; (Pleasanton, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Arevo, Inc. |
Saratoga |
CA |
US |
|
|
Family ID: |
59275437 |
Appl. No.: |
14/297185 |
Filed: |
June 5, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61951720 |
Mar 12, 2014 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08J 2377/00 20130101;
C08J 2481/06 20130101; C08J 2479/08 20130101; B29C 48/92 20190201;
C08L 69/00 20130101; C08J 2469/00 20130101; C08L 81/06 20130101;
B29C 48/022 20190201; C08J 3/203 20130101; B33Y 70/00 20141201;
C08L 67/02 20130101; C08L 71/00 20130101; C08L 71/123 20130101;
C08J 2471/12 20130101; B33Y 10/00 20141201; C08G 2650/40 20130101;
B29C 64/141 20170801; C08J 2367/02 20130101; C08J 2369/00 20130101;
B29C 64/118 20170801; B29C 48/02 20190201; C08J 3/005 20130101;
B29L 2031/731 20130101; C08L 71/00 20130101; C08L 81/06 20130101;
C08L 71/00 20130101; C08L 79/08 20130101 |
International
Class: |
C08J 3/00 20060101
C08J003/00; B33Y 70/00 20060101 B33Y070/00; B29C 67/00 20060101
B29C067/00; B29C 47/00 20060101 B29C047/00; C08J 3/20 20060101
C08J003/20; C08L 67/02 20060101 C08L067/02; C08L 81/06 20060101
C08L081/06; C08L 79/08 20060101 C08L079/08; C08L 77/00 20060101
C08L077/00; C08L 71/12 20060101 C08L071/12; C08L 69/00 20060101
C08L069/00; B33Y 10/00 20060101 B33Y010/00; C08L 71/00 20060101
C08L071/00 |
Claims
1. A method for forming a blended material for use as a deposition
material in a fused filament fabrication (FFF) printer, the method
comprising: providing a first amount of a semi-crystalline material
and a second amount of an amorphous material; physically mixing the
first amount of the semi-crystalline material and the second amount
of the amorphous material, wherein the weight ratio of the first
amount to the second amount is 50:50 or higher; heating the mixed
material to a temperature that is above the melting point of the
semi-crystalline material and above the glass transition
temperature of the amorphous material to form a blended material;
and extruding the blended material through an extruder die for use
in the FFF printer.
2. The method of claim 1, wherein the step of physically mixing
includes mixing the semi-crystalline and amorphous materials such
that the weight ratio of the first amount to the second amount is
between 60:40 and 80:20, inclusive.
3. The method of claim 1, wherein the semi-crystalline material
includes polyether ether ketone.
4. The method of claim 2, wherein the amorphous material includes
polyphenylsulfone.
5. The method of claim 2, wherein the amorphous material includes
polyethersulfone.
6. The method of claim 2, wherein the amorphous material includes
polyetherimide.
7. The method of claim 2, wherein the amorphous material includes a
polyarylsulfone.
8. The method of claim 2, wherein the amorphous material includes
at least one of the following materials: polyphenylene oxides,
acrylonitrile butadiene styrene, methyl methacrylate acrylonitrile
butadiene styrene copolymer, polystyrene, and polycarbonate.
9. The method of claim 1, wherein the amorphous material includes
at least one of the following materials: polyphenylene oxides,
acrylonitrile butadiene styrene, methyl methacrylate acrylonitrile
butadiene styrene copolymer, polystyrene, and polycarbonate.
10. The method of claim 1, wherein the semi-crystalline material
includes at least one of the following materials: polyamide,
polybutylene terephthalate, and poly(p-phenylene sulfide).
11. The method of claim 10, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
polyamide and polyphenylene oxide together.
12. The method of claim 10, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
polybutylene terephthalate and polycarbonate together.
13. The method of claim 10, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
poly(p-phenylene sulfide) and polyetherimide together.
14. The method of claim 1, wherein the step of providing a
semi-crystalline material includes providing at least two different
semi-crystalline materials.
15. The method of claim 1, wherein the step of providing an
amorphous material includes providing at least two different
amorphous materials.
16. The method of claim 1, wherein the step of providing a
semi-crystalline material and an amorphous material includes
providing at least two different semi-crystalline materials and at
least two different amorphous materials.
17. The method of claim 1, wherein the step of physically mixing
includes mixing the first amount of the semi-crystalline material,
the second amount of the amorphous material and a third amount of a
filler material whose melting temperature is higher than the
semi-crystalline material.
18. The method of claim 17, wherein the filler material includes
one or more of the following materials: carbon fibers, glass fibers
and aramid fibers.
19. A method for operating a fused filament fabrication (FFF)
printer comprising: providing a heat blended material adapted to be
fed to a FFF printer, wherein the blended material contains an
amorphous material and a semi-crystalline material; feeding the
blended material to the FFF printer; heating the blended material
to a temperature that is above the melting point of the
semi-crystalline material and above the glass transition
temperature of the amorphous material; and depositing, by a
printing head of the FFF printer, the heated material in a selected
pattern in accordance with a mathematical model of a 3D object to
form the 3D object.
20. The method of claim 19, wherein the step of providing a blended
material includes providing the blended material whose weight ratio
of the semi-crystalline material to the amorphous material is 50:50
or higher.
21. The method of claim 19, wherein the step of providing a blended
material includes providing the blended material whose weight ratio
of the semi-crystalline material to the amorphous material is
between 60:40 and 80:20, inclusive.
22. The method of claim 19, wherein the first semi-crystalline
material is polyether ether ketone.
23. The method of claim 22, wherein the amorphous material includes
polyphenylsulfone.
24. The method of claim 22, wherein the amorphous material includes
polyethersulfone.
25. The method of claim 22, wherein the amorphous material includes
polyetherimide.
26. The method of claim 22, wherein the amorphous material includes
a polyarylsulfone.
27. The method of claim 22, wherein the amorphous material includes
at least one of the following materials: polyphenylene oxides,
acrylonitrile butadiene styrene, methyl methacrylate acrylonitrile
butadiene styrene copolymer, polystyrene, and polycarbonate.
28. The method of claim 19, wherein the amorphous material includes
at least one of the following materials: polyphenylene oxides,
acrylonitrile butadiene styrene, methyl methacrylate acrylonitrile
butadiene styrene copolymer, polystyrene, and polycarbonate.
29. The method of claim 16, wherein the semi-crystalline material
includes at least one of the following materials: polyamide,
polybutylene terephthalate, and poly(p-phenylene sulfide).
30. The method of claim 29, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
polyamide and polyphenylene oxide together.
31. The method of claim 29, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
polybutylene terephthalate and polycarbonate together.
32. The method of claim 24, wherein the step of physically mixing
the semi-crystalline and amorphous materials includes mixing
poly(p-phenylene sulfide) and polyetherimide together.
33. The method of claim 19, wherein the step of providing operation
of providing a heat blended material includes: physically mixing a
first amount of the semi-crystalline material and a second amount
of the amorphous material, wherein the weight ratio of the first
amount to the second amount is 50:50 or higher; heating the mixed
material to a temperature that is above the melting point of the
semi-crystalline material and above the glass transition
temperature of the amorphous material to form a blended material;
and forming a filament of the blended material by extruding the
blended material through a die of an extruder.
34. The method of claim 19, wherein the step of providing a heat
blended material includes providing the heat blended material
containing a filler material whose melting temperature is higher
than the semi-crystalline material.
35. The method of claim 34, wherein the filler material includes
one or more of the following materials: carbon fibers, glass fibers
and aramid fibers.
36. A composition for use in a fused filament fabrication (FFF)
printer comprising: a roll of filament adapted to be fed to the FFF
printer for printing a 3D object, wherein the filament includes a
heated blend of a first amount of a semi-crystalline material and a
second amount of an amorphous material, wherein the weight ratio of
the first amount to the second amount is 50:50 or higher.
37. The composition of claim 36, wherein the weight ratio of the
first amount to the second amount is between 60:40 and 80:20,
inclusive.
38. The composition of claim 36, wherein the weight ratio of the
first amount to the second amount is between 80:20 and 90:10,
inclusive.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/951,720, filed Mar. 12, 2014, entitled
"COMPOSITIONS AND METHODS FOR USE IN FUSED FILAMENT FABRICATION
PROCESSES", which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention pertains to 3D printing and in particular,
materials for use in fused filament fabrication.
BACKGROUND OF THE INVENTION
[0003] Fused filament fabrication ("FFF"), also known as fused
deposition modeling, is an additive manufacturing technology
typically used for modeling, prototyping, and in some cases even
production applications. This process fabricates a
three-dimensional ("3D") object from a mathematical model of the
object using materials such as thermoplastics and metals that are
typically in the form of a filament. In the case of a thermoplastic
material, the object is built by feeding a thermoplastic filament
into a heated extrusion head. The thermoplastic is heated past its
glass transition temperature and then deposited by the extrusion
head as a series of beads in a continuous motion. After deposition,
the bead quickly solidifies and fuses with the beads next to and
below it. The nozzle of the extrusion head follows a tool-path
controlled by a computer-aided manufacturing (CAM) software
package, and the object is built from the bottom up, one layer at a
time.
[0004] The thermoplastics used for fused filament fabrication
include, for example, acrylonitrile butadiene styrene (ABS), methyl
methacrylate acrylonitrile butadiene styrene copolymer (ABSi),
polyphenylsulfone (PPSU), and polycarbonate (PC), among others. A
commonality among the aforementioned thermoplastics is that they
are all amorphous polymers. Amorphous polymers have a randomly
ordered molecular structure. These polymers are characterized by
the lack of a distinct melting point; the material increasingly
softens and viscosity lowers with increasing temperature. The
viscosity at which these amorphous polymers can be extruded is high
enough that their shape will be substantially maintained after
extrusion, enabling them to solidify rapidly. Also, when the
extruded material is deposited on a previously deposited layer
during the formation of an object via 3D printing, the two layers
readily bond.
[0005] Unfortunately, amorphous polymers tend to have poor chemical
resistance, lower heat resistance, lower dimensional stability and
higher creep. That is why most objects formed via fused filament
fabrication cannot be used in more demanding applications such as
in aerospace, oil a gas and healthcare industries. Those industries
primarily require semi-crystalline material which is conventionally
used in an injection moulding process to manufacture 3D
objects.
[0006] However, attempts to "print" the semi-crystalline material
with a fused filament fabrication process have been unsuccessful.
This is because the highly viscous nature of the material causes
clogging in the extrusion printhead and even when printed, the
semi-crystalline material does not solidify fast enough to hold its
shape.
[0007] Therefore, it would be desirable to provide a composition
for 3D printing which has better chemical resistance, higher heat
resistance, higher dimensional stability and lower creep than the
conventional amorphous materials favored in the prior art, such
that 3D objects made with the improved composition can be used as a
working part in more demanding applications such as in aerospace,
healthcare and oil & gas applications. It would also be
desirable to provide a method of using the improved composition in
3D printing.
SUMMARY OF THE DISCLOSURE
[0008] In accordance with an illustrative embodiment, a method for
forming a blended material for use as a deposition material in a
fused filament fabrication printer is provided. A semi-crystalline
material and an amorphous material are physically mixed at an
appropriate ratio. The mixed material is then heated to a
temperature that is above the melting point of the semi-crystalline
material and above the glass transition temperature of the
amorphous material to form a blended material. The blended material
is then extruded through an extruder die for use in the FFF
printer. Advantageously, the blended material allows printing of a
3D object with semi-crystalline material to provide increased
chemical resistance and superior mechanical strength.
[0009] In another aspect of the present invention, a method of
operating a FFF printer is provided. A heat blended material
adapted to be fed to a FFF printer is provided, wherein the blended
material contains an amorphous material and a semi-crystalline
material. In the FFF printer, the blended material is heated to a
temperature that is above the melting point of the semi-crystalline
material and above the glass transition temperature of the
amorphous material. A printing head of the FFF printer then
deposits the heated material in a selected pattern in accordance
with a mathematical model of a 3D object to form the 3D object.
[0010] In yet another aspect of the present invention, a
composition for use in a fused filament fabrication (FFF) printer
is provided. The composition includes a roll of filament adapted to
be fed to the FFF printer for printing a 3D object. The filament
includes a heated blend of a first amount of a semi-crystalline
material and a second amount of an amorphous material, wherein the
weight ratio of the first amount to the second amount is 50:50 or
higher.
BRIEF DESCRIPTION OF THE DRAWING
[0011] FIG. 1 is a flowchart of a method of fabricating a blended
extrudate of amorphous and semi-crystalline materials according to
an aspect of the present invention.
[0012] FIG. 2 is a flowchart of a method of fabricating a filament
roll from the blended extrudate which is suitable to be fed into a
fused filament fabrication printer according to an aspect of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Printing with the blended material results in 3D objects
having more desirable mechanical properties and chemical resistance
than would be possible using an amorphous material alone. This
results from the presence of the semi-crystalline material in the
blend, which is characterized by significantly better chemical
resistance and mechanical properties such as tensile strength.
[0014] In one embodiment, the blend is a mixture of
polyphenylsulfone (PPSU), representing the amorphous polymer, and
polyether ether ketone (PEEK) as the semi-crystalline material.
[0015] In some other embodiments, other amorphous materials, such
as other polyarylsulfones (e.g., polyethersulfone (PESU),
polysulfone (PSU), etc.) can be used in conjunction with PEEK to
form a blended material in accordance with the present teachings
and suitable for use in a fused filament fabrication process. Still
further, other amorphous materials can be used in conjunction with
PEEK or other semi-crystalline materials to form a blended material
in accordance with the present teachings and suitable for use in a
fused filament fabrication process. Such other amorphous materials
include, for example and without limitation, polyetherimide (PEI),
polyphenylene oxides (PPOs), acrylonitrile butadiene styrene (ABS),
methyl methacrylate acrylonitrile butadiene styrene copolymer
(ABSi), polystyrene (PS), and polycarbonate (PC).
[0016] In some other embodiments, polyaryletherketones (PAEKs)
other than PEEK can be used as the semi-crystalline component of
the blended material. In still further embodiments, other
semi-crystalline thermoplastics, for example and without
limitation, polyamide (PA), polybutylene terephthalate (PBT),
poly(p-phenylene sulfide) (PPS) can be blended with appropriate
amorphous thermoplastics to form a blended material in accordance
with the present teachings. For example, some other suitable
blended materials include PA (semi-crystalline) and PPO
(amorphous), PBT (semi-crystalline) and PC (amorphous), and PPS
(semi-crystalline) and PEI (amorphous).
[0017] In one exemplary embodiment, the weight ratio of
semi-crystalline material to amorphous material in the blend is in
a range of about 50:50 to about 95:05, inclusive, or about 50:50 to
about 90:10, inclusive. Preferably, the weight ratio of
semi-crystalline material to amorphous material in the blend is
between 60:40 and 80:20, inclusive. In certain applications,
however, the weight ratio of semi-crystalline material to amorphous
material in the blend could be between 80:20 and 90:10, inclusive,
or 80:20 or greater to obtain the most benefit of the superior
properties of the semi-crystalline material so long as the blend
viscosity is sufficiently high at the operating temperature to
preserve its shape upon printing through the extrusion head of the
fused filament fabrication printer. The ratio selected for any
particular application may vary primarily as a function of the
materials used and the properties desired for the printed
object.
[0018] Since a semi-crystalline polymer by itself has a relatively
high viscosity, it would be problematic if not impossible to
extrude the material through an extrusion head of a fused filament
fabrication printer. However, according to the present invention,
the presence of an amorphous polymer in the blend exhibits the
relatively more desirable rheological properties characteristic of
an amorphous polymer. In other words, the amorphous polymer in the
blend decreases the viscosity sufficiently to allow printing of the
material through the fused filament fabrication printer.
[0019] In another embodiment, the blended material may include two
or more semi-crystalline materials and/or two or more amorphous
materials. In embodiments in which multiple semi-crystalline
materials or multiple amorphous materials are used to form the
blended material, the total amount of each type of material
(semi-crystalline or amorphous) should fall within the ratio
guidelines provided above.
[0020] In yet another embodiment, a solid non-polymer filler
material having a higher melting temperature than both the
amorphous material and semi-crystalline material can be added to
the blend to improve mechanical properties of the 3D objects. The
amount of the filler material by weight is up to about 60%, and
more preferably between 5% and 20% of the total blend. The filler
material can include chopped carbon fibers, chopped glass fibers,
chopped aramid/Kevlar fibers. Preferably, the fibers are chopped in
1-3 mm in length and are suspended in the blend during its
fabrication. In an exemplary embodiment, the chopped fibers are
encapsulated or coated with resin.
[0021] Referring to FIG. 1, the blend is prepared as follows. The
materials to be blended are typically provided in pellet or powder
form. In step 100, the materials are dried in a dryer to remove
moisture in order to prevent hydrolysis of polymer that can reduce
polymer chain length resulting in poorer properties. In step 102,
the dried materials in powder form are physically and thoroughly
mixed in a mixing device. In step 104, the mixed semi-crystalline
and amorphous materials are then fed to a hopper of an extruder. In
one embodiment, a twin-screw extruder is used to melt blend the
materials and then extrude the blended material into a strand.
[0022] In case a filler material is used, it can be added during
step 102 or 104 or in step 114 as will be discussed later herein.
In the extruder, the mixed materials are "melted" (step 106). In
accordance with one embodiment, the melt blending is performed at a
temperature that is: (a) above the glass transition temperature of
the amorphous polymer materials, preferably at a temperature at
which the polymer is fluid; (b) above the melting point of
semi-crystalline polymer materials; and (c) below the polymer
degradation temperature of all amorphous and semi-crystalline
materials. In case more than one amorphous polymer material is used
in the blend, the melt blending is performed at a temperature that
is above the glass transition temperature of all the amorphous
polymer materials, at which the polymers behave like a fluid.
Likewise, in the case of more than one semi-crystalline polymer
materials, the melt blending is performed at a temperature that is
above the melting point of all the semi-crystalline polymer
materials that are used in the blend.
[0023] It has been found that this methodology provides good
dispersion of the components and enables good viscosity management
(controlling viscosity so that it is in an appropriate range for
extrusion) during 3D printing by FFF.
[0024] Table 1 below depicts the glass transition temperature (Tg)
or melting temperature (Tm), and the melt processing temperature
for several components used in forming blended materials in
accordance with the present teachings.
TABLE-US-00001 TABLE 1 Glass Transition, Melting, and Melt
Processing Temperature Melting Typical Melt Glass Transition
Temperature, Processing Temperature, T.sub.g T.sub.m Temperature
Material Type <.degree. F.> <.degree. F.> <.degree.
F.> PEEK Semi- 650 670-700 Crystalline PPSU Amorphous 428 --
650-750 PEI Amorphous 420 -- 660-750 PESU Amorphous 437 --
650-725
[0025] In step 108, the melted material passes through a die of the
twin-screw extruder and is extruded. In one embodiment, the
resulting extrudate is typically formed into a strand, which is
typically 1/4-1/2 inch in diameter. The melt processing temperature
(i.e., the temperature of the material as it is extruded through an
extrusion head of a fused filament fabrication printer), as
provided in Table 1, will typically be near the temperature at
which the materials are melt blended. For example, PEEK
(semi-crystalline) and PPSU (amorphous), PEEK (semi-crystalline)
and PEI (amorphous), and PEEK (semi-crystalline) and PESU
(amorphous) can be melt blended at about 690.degree. F. The melt
processing temperature, as per Table 1, will be a similar
temperature.
[0026] Of course, the melt processing temperature for the blended
material will be dictated by the highest melting temperature or
highest glass transition temperature of all the amorphous and
semi-crystalline materials in the blend, whichever is higher. In
the case of the PEEK/PPSU blend, the melting temperature of PEEK is
higher than the glass transition temperature of the PPSU. Thus, the
melt processing temperature of the blend during printing is in the
range of 670-700.degree. F. at the extrusion printhead of the FFF
printer.
[0027] After extrusion, in step 110, the strand is cooled, such as
in a water bath. In one embodiment, the size of the extrusion die
is such that the strand is in a form of a filament having a
diameter of 1-2 mm. The filament is then wound as a roll of
filament, which can be fed directly into the FFF printer.
Alternatively, in step 112, the strand is cut into small pellets
for storage. In that case, the pellets will need to be reprocessed
into a filament of 1-2 mm in diameter which is adapted for direct
feeding into the FFF printer as illustrated in FIG. 2.
[0028] In step 114, the pellets containing the blended materials
from step 112 are fed into a hopper of an extruder such as a single
or twin-screw extruder. If the filler material is involved, it can
be added in this step instead of step 102 or 104. In step 116, the
blended pellets are "melted" in the extruder. Similar to step 106,
the melting is performed at a temperature that is: (a) above the
glass transition temperature of the amorphous polymer materials,
preferably at a temperature at which the polymer is fluid; (b)
above the melting point of semi-crystalline polymer materials; and
(c) below the polymer degradation temperature of all amorphous and
semi-crystalline materials. The temperature in the extruder for
melting the PEEK (semi-crystalline) and PPSU (amorphous), PEEK
(semi-crystalline) and PEI (amorphous), and PEEK (semi-crystalline)
and PESU (amorphous) blend is about 690.degree. F.
[0029] In step 118, the melted material passes through a die of the
extruder and is extruded into a filament, which is typically 1 to 2
mm in diameter. After extrusion, in step 120, the filament is
cooled, such as in a water bath and is rolled onto a roll as a
final product in step 122, which is suitable to be fed directly
into the FFF 3D printer.
[0030] To print a 3D object, the filament from the filament roll of
the heat blended material is fed to the FFF printer. The filament
being fed is then heated by a heater block of the FFF printer to a
useable temperature which is above the melting point of the
semi-crystalline material and above the glass transition
temperature of the amorphous material. The FFF printer then
deposits the heated material in a selected pattern layer by layer
in accordance with a mathematical model of the 3D object in order
to fabricate the 3D object.
[0031] As a consequence of the aforementioned desired temperature
guidelines, those skilled in the art will appreciate that not all
combinations of the aforementioned semi-crystalline thermoplastics
and amorphous thermoplastics will be well suited to melt blending
for forming the blended material. For example, the thermal
transition temperatures should satisfy the aforementioned
guidelines and the materials need to be miscible or otherwise
compatible. Using this disclosure and readily available reference
sources, it is within the capabilities of those skilled in the art
to appropriately pair a semi-crystalline thermoplastic and an
amorphous thermoplastic to create a blended material in accordance
with the present invention.
[0032] The above disclosure is intended to be illustrative and not
exhaustive. This description will suggest many modifications,
variations, and alternatives may be made by people of ordinary
skill in this art without departing from the scope of the
invention. Those familiar with the art may recognize other
equivalents to the specific embodiments described herein.
Accordingly, the scope of the invention is not limited to the
foregoing specification.
* * * * *